Professor of the Prehistory of Humanity, University of Vienna; Author, The Artificial Ape

Reader in Archaeology at the University of Bradford

'What now?' depends on our analysis of what happened and 'What happened?' depends on perspective. For most westerners, the twin towers were two office blocks for global traders. For the charismatic, inward-looking seventeenth child of a family of 50 Saudi Arabian siblings, Osama bin Laden, they did not simply symbolize the horns of Satan stretching from earth towards heaven, they were their physical reality. The actions of Mohamed Atta and Marwan Al-Shehhi, the respective pilot-murderers who destroyed the World Trade Centre on 11th of September 2001 have been attributed to their religion both by us and by those who supported them. They cannot now tell us their own justification but, even if they were also able to say it was religion, I would remain unconvinced. Religious and political ends may have provoked this tragedy, but they needed a substrate to act on, one that is not created by religion itself. Many fundamentalist Muslims would not and could not have done what they did. It takes a particular type of personality, under particular circumstances.

It was only on the 10th of May 2001 that Judy Kirby drove her nephew Jeremy Young to an Indianapolis branch of Toys R Us to get his tenth birthday present, picked up her own three children and then deliberately drove them all at speeds approaching 100 miles an hour down the wrong side of Ind. 67. A witness saw a small boy on the front seat on his knees, gripping terrified onto the dash before the spectacular explosion that killed all the children in the car, plus two in an oncoming van and their father. Bizarrely, Kirby survived and is now serving 215 years. She was not a fundamentalist Muslim funded by bin Laden. She was a disturbed, depressed and aggressive human being with a grim romantic streak who wanted to commit suicide infamously. One look at Mohamed Atta's face in the published photo tells me that here was a protagonist who (while at one level a well-educated and financially well-off man) was profoundly depressed too. In Islam, as in many cultures both now and in the past, suicide is deeply shameful. This can give the road to martyrdom powerful appeal.

Human beings are individually capable of holding mutually contradictory beliefs and also of being guided as much by uncognized emotion as any species of logic, whether religious or materialist. Atta, as he flew into the side of the World Trade Centre may in one way have believed in a martyr's reward in paradise. At another level he may have hoped for oblivion, an end to inner pain, by committing a personal suicide that was masked in a cloak of fanatical religion. But he was one of 19 others, spread among the four hijacked planes. None of them quite needed Judy Kirby's level of lone resolve to do what they did. They had invidious backup and they had each other. So it was much easier.

Depressed-aggressive suicide-murderers are likely to be people who feel unloved and unvalued, the very opposite of the New York firemen and self-sacrificing passengers aboard the fourth plane, scuppered in the Pennsylvania woods. Actions that create more desperate and bitter people will contribute to the world becoming more dangerous for us all. What now? — it depends on the quality of our humanity.